Hydraulic control for machine tools



A1915125, 1950 r F. M. TOMLINSON 2,505,221 mnmuuc comon FOR MACHINE *roons Filed Dec. 19," 1945 I 4 Sheets-Sheet 1 fTOE/YIYG April 25,1950 v F. M. ToMLiNsoN 2,505,221

.. mmzwuc CONTROL FOR MACHINE TOOLS 4 Sheets-Sheet 2 -FIL Filed'Dec. 19, 1 945 PUMP 5456 7019 valve 0mm: 01. arc/l INVENTOR. 54y M2 ToML/ms'o/v April 25, 1950 F. M. TOMLINSQN mmuuuc comer. FOR MACHINE Tools 4 Sheets-Sheet 3 Filed Dec; 19. 1945 t his &5 with 65 Q SsNQk WINK NP h April 25, 1950 I F. M. TOMLINSON HYDRAULIC comm. FOR momma: TOOLS 4 Sheets-Sheet 4 Filed Dec. 19. 1945 Patented Apr. 25, 1950 UNITED STATES PATENT OFFICE Fay M. Tomlinson, Lakewood, Ohio, asslgnor to The Warner & Swascy Company, Cleveland, Ohio, a corporation of Ohio Application December 19, 1945, Serial No. 636,039

This invention relates to a machine tool and particularly to an improved mechanism for con- 12 Claims. (Cl. 1924) trolling the speeds, direction of operation and the starting and stopping of a movable part of a machine tool such as the work spindle.

An object of the invention is to increase the efficiency of a machine tool as, for instance, a lathe, by enabling the operator to effect with a minimum of effort and skill on his part the changes in speed, direction of operation and the starting and stopping of a movable part of the machine tool, as for instance the work spindle.

A more specific object is to increase the efficiency of a machine tool, such as a lathe, by enabling the operator to effect with a minimum of attention and skill on his part the starting and stopping of the work spindle in-the headstock, the directionof rotation of said spindle and the shifting of the gears of the change speed transmission in the headstock to vary the speed of rotation of the spindle.

Another object of the invention is to accomplish the objects above enumerated in such a way as to reduce the wear and tear on the change speed transmission and thus increase the life of the machine and keep maintenance costs to a minimum.

Another object of the invention is to provide in a machine tool of the type having a movable part, a change speed transmission for moving said part at different speeds in opposite directions and means for selecting or preselecting the speed of said part for the different operative steps of a work cycle; improved and novel means for attaining the selected or preselected speed of said part and which means automatically effects a complete speed changing cycle of operation after the operator has, manually initiated said cycle of operation.

Another object is to provide in a machine tool such as referred to in the last named object a safety feature whereby the means for selecting or preselecting the different speeds of the movable part cannot be operated by the operator during the automatic cycle of operation of the speed changing mechanism.

Another object of the invention is to attain the above mentioned objects by means of an improved and novel pressure fluid operated mechanism for efiecting the automatic cycle of the speed changing operation. I

Another andmore detailed object of the invention is to provide a pressure fluid operated mechanism as referred to in the last object and wherein the automatic cycle of operation includes the disengagement of the clutch, the initiation of a slow speed non-working drive to the transmission to facilitate the shifting of the shiftable elements, a shifting of said elements in a predetermined way and the reengagement of the main drive clutch.

Another object is to provide a safety feature to prevent injury to the shiftable gears of the transmission byincluding in the fluid operated mechanism provision for automatically arresting shifting movement of the gear shifting members whenever the gears to be intermeshed cannot properly engage, then automatically driving the transmission at a slow non-working speed to cause the teeth of said gears to assume a relationship wherein the gears may be properly intermeshed and then reestablishing the gear shifting movement of said members.

Another object is to provide an improved braking means for stopping the movement of the movable part quickly and for then holding said part in stopped position and wherein the brake is applied for a predetermined period of time with a maximum pressure to overcome quickly the momentum of the movable part after which the brake is held applied with a reduced relatively low predetermined pressure to hold the part in stopped position although permitting slow manual movement thereof for loading and unloading purposes.

Another object is to provide a fluid pressure operated mechanism as referred to in the last object and wherein a single manually moved control member, in addition to initiating the automatic cycle of the speed changing operation may selectively control without initiating said cycle the direction of operation of the change speed transmission and the engagement and disengagement of the main clutch and the application of a brake means.

Further and additional objects and advantages of the invention not hereinbefore referred to will become apparent hereinafter during the detailed description of an embodiment of the invention illustrated in the accompanying drawings wherein, 1 Fig. 1 is a front elevational view of a turret lathe to which the invention has been applied for purposes of illustration.

Fig. 2 is a developed and diagrammatic view illustrating the embodiment of the invention in connection with the change speed gearing that drives the work spindle in the headstock of a lathe.

Fig. 3 is a diagrammatic view of the control mechanism and the pressure fluid circuit for operating the same, with the parts of the mechanism shown in positions they occupy when the work spindle is operating in the forward direction.

Fig. 4 is a view similar to Fig. 3 with the par of the control mechanism in a different relationship.

Fig. 5 is a sectional view taken along line 5-5 of Fig. 3.

. described.

Referring to Fig. 2 wherein the change speed gearing is illustrated, it will be seen that a power source, in this instance a pulley I8, is secured to the main drive shaft l9 and that said pulley can be driven in any suitable manner. A pressure fluid operated forward clutch 26 and a pressure fluid operated reverse clutch 2| are mounted on the main drive shaft l9 and when actuated cause the gear 26 or the gear 22, respectively, to rotate with the shaft IS on which said gears are normally freely rotatable. The gear 22 meshes with an idler gear 23 which in turn meshes with a gear 24 fixed to a shaft 25, whereby said shaft 25 may be driven by the shaft l9 but in the opposite or reverse direction. The gear 26 meshes with a gear 21 fixed to said shaft 25 whereby said shaft may be driven by the shaft IS in the same or forward direction.

A three-step gear cone composed of gears 28, 23 and 36 is splined to shaft 25 intermediate the gears 24 and 21 for rotation with said shaft and for shifting movement axially thereof, and said gears 28, 29 and 36 mesh, respectively, with gears 3|, 32 and 33 fixed toa shaft 34. .It will be noted that shaft, 34 can be driven at any one of three speeds in either the forward or reverse direction.

The gear 3| constantly meshes with a gear 35 formed on the sleeve 36 that is freely rotatable on the spindle I1 but is held against axial movement thereon. The sleeve 36 is also provided with a gear 31 located adjacent the opposite end of the sleeve from the gear 35. The gears 35 and 31 mesh, respectively, vwith gears 38 and 39 of a shiftable rear two-step gear cone that is splined to the shaft 46. It will be seen that the shaft 46 can be driven at any one of six speeds in either the forward or reverse direction.

The shaft 46 also has splined thereto a shiftable front two-step gear cone formed of gears 4| and 42 with the gear 4| adapted to be intermeshed with gear 43 fixed to the spindle I'I, while the gear 42 can be intermeshed with the gear 46 also fixed to said spindle, wherefore it will be seen that in the present illustration the spindle can be driven from the main drive shaft at drive shaft IE3 at a slow non-working speed, hereinafter referred to as a crawl speed by mechpurpose of facilitating the shifting of the gears.

anism which will now be described, and for the A bevel gear 45 is fixed to the drive shaft l9 and meshes with another bevel gear 46 fixed to a short shaft 41 that is rotatably supported in the headstock and extends transversely of the shaft 25. The shaft 41 has fixed thereto intermediate its ends a worm 48 which meshes with a worm wheel that forms part of the normally disengaged pressure fluid operated crawl speed" clutch 49 mounted on the shaft 25 and the action of which will be described hereinafter.

The shiftable three-step gear cone on the shaft 25 and the rear and front two-step gear cones on the shaft 4|) are shifted, respectively, by gear forks 50, 5| and 52 movably mounted in the headstock and operatively interconnected with said gear cones as indicated by the dash and dot lines in Fig. 2 and as will be well understood in the art.

The spindle speed for each operative step of a work cycle may be selected at the end of the preceding operative stepor it may be preselected during the preceding step by selecting or preselecting means in the form of spools 53 and 54 splined on an indexible shaft 55 to be indexed with said shaft and to be moved endwise thereon from a separated indexing position toward each other to actuate the gear forks 56, 5| and 52 located intermediate the spools in a position to be engaged by the cooperating series of projections on the adjacent faces of the spools, as clearly explained in detail in the patent to Max E. Lange 2,068,552, issued January 19, 1937. The shaft 55 extends outwardly of the headstock and can be indexed by means of a hand wheel or knob 56 fixed thereto. The shaft 55 inwardly of the headstock also has fixed thereto an interlock drum 5'! (see Figs. 2, 3 and 4) providedin its periphery with a plurality of circumferentially spaced openings or recesses 58, the purpose of which will later be pointed out.

The hand wheel or knob 56 and the headstock may be provided with suitable indicia and pointer means, not shown, to indicate to the operator in relation to spindle speeds the various indexed positions of the spools or the shaft 55 may be operatively interconnected with an indicating device 59 located on the headstock and functioning to indicate to the operator the various indexed positions of the spool in relation to spindle speeds and also in relation to the different operative steps of the work cycle. Although various forms of indicating devices might be employed for this purpose the one shown herein is similar to the indicating device disclosed in the patent to Max E. Lange No. 2,169,765, issued August 15, 1939.

Referring now to the diagrammatic view of the control mechanism and the pressure fluid circuit for operating the same shown in Figs. 2, 3 and 4, it will be noted that pressure fluid, in this instance, a liquid, is pumped into the circuit from a reservoir or sump 66 through a filter 6| by a constantly operating pump 62. A relief valve 63 well known in the art is connected to the pump and to the hydraulic circuit lines 64 and 65 and to the reservoir 66 by the line 63a, wherefore fluid is forced into said conduit lines at a predetermined pressure. Wherever in the diagram a conduit line bears an arrow it will be understood that such line leads to the sump similarly as does line 63a. The line 65 is connected to a valve 66, hereinafter designatedas the shift valve. The pressure fluid when said shift valve 66 is in its normal inactive position, as illustrated in Fig. 3, enters the annular space 61 surrounding the valve plunger 68 and intermediate the lands 66 8 and 10. The pressure fluid at this time leaves the annular space 61 of the shift valve 06 and passes into the line 'II which is connected to the inlet of the selector valve I2.

The selector valve 12 contains a rotatable core or plug I3 which is moved to its various positions in the valve casing by means of a manually operated lever I4 that is operatively connected to the core or plug and is located on the front side of the head stock where it is readily accessible to the operator (see Fig. 1). Said lever-I4 in addition to having a rocking movement substantially in the plane of' the front side of the headstock to rock the valve core or plug I3 also has an inward rocking movement in a direction transverse to its first mentioned rockingmovement for the purpose of moving the shift valve plunger 68 as later to be explained. The valve core or plug I3 is provided with an axially extending bor'eIB to which the line II is connected. The core or plug I3 is of less diameter than the internal diameter of the valve plug.

when the lever I4 of the selector valve I2 isin the full line position of Fig. 3, i. e., the forward position, the passage I6 is in registry with the port J1 and to which port the line I8 is connected. Consequently the pressure fluid 'flowing through line H passes through the selector valve core or plug and into the line I8 at this time. The line I8 is connected to a relief valve I9 and said relief valve I9 is also connected with a line 80 and with a sump return line 8I illustrated in part and similar to the line 63a. The line 80 is interconnected with the line 02 that communicates with 1 the cylinder of the pressure fluid operated forward clutch 20. The forward clutch 20 is composed of a cylinder fixedly supported in th headstock and in which is slidably mounted a piston 83 that is splined on the shaft I9 and said piston carries on its right hand face, as viewed in Fig. 3, a friction plate 04 which engages a friction plate 85 carried by the hub of the gear 26 that is freely rotatable on the shaft I9. It will be seen that when the lever I4 is in the full line position of Fig. 3 and pressure fluid is in line H, said fluid flows through the selector valve I2, through the relief valve I9, lines 80 and 82 and into the cylinder of the forward clutch 20 to move the piston 83 thereof toward the right to engage the friction Y turn to the sump through the port 86 of the valve housing and the line 81 which is extended to the sump, and at such time the forward clutch will be disengaged and the shaft I9 will rotate freely relative to the gear 26. Assuming that the lever 14 is moved to the dash and dot line position identified in Fig. 3

reverse position shown therein, the passage I6 in the core or plug registers with the port in the housing of 'the selector valve I2, and said port'90 is connected with the line 9| that extends to the cylinder of the. reverse clutch 2I. The reverse clutch 2| is identical in structure with the fora ward clutch 20 and includes a piston slidable in the cylinder and splined to the shaft I9 and having a friction plate engageable with a friction plate on the hub of the gear 22 that is freely rotatable on the shaft I9. Consequently when the lever I4 of the selector valve I2 is in the reverse position just described pressure fluid is passing from the line II through said selector valve and through the line 9I to the cylinder of the reverse clutch 2I and the piston of said clutch has moved to frictionally engage the plates and cause the gear 22 to rotate with the shaft I9.

It will be understood that when the control lever I4 of the valve I2 is moved from reverse position into any of the other positions indicated, then the pressure fluid in the reverse clutch and in the line 9I returns to the reservoir or sump by way of the selector valve housing and the port 86 as described relative to the forward clutch 20.

When the lever is moved to brake position, indicated by dot and dash lines in Fig. 3 and by full lines in Fig. 4, the passage I6 of the valve core or plug registers with the port 92 in the selector valve housing intermediate the ports 88 and 90. The port 92 communicates with the line 93 that extends to and communicates with the brake cylinder 94. A piston 95 is slidable in the brake cylinder 94 and the piston rod extends outwardly of said cylinder and has secured to its outer end a brake shoe or band 96 adapted to engage with the periphery of an annular flange 91 on the work spindle II.

It will be seen that when the control lever I4 is moved to brake position (see Fig. 4) then the line H is connected through the selector valve with the line 93 and pressure fluid at line pressure enters the brake cylinder 94 to move the piston 95 thereof against the action of the spring 98 to engage the brake shoe 96 with the flange 91 with maximum pressure and hence apply a maximum braking action to quickly overcome the momentum and stop the rotation of the spindle II.

When the lever I4 of the selector valve is moved to brake position and pressure fluid at full line pressure is flowing into the line 93 and into the brake cylinder 95, said pressure fluid also flows from the line 93 into the line 99 which extends to the brake valve I00. The brake valve I00 is provided with a passage IOI that extends to and communicates with the valve chamber I02 in which is slidably mounted a valve plunger which has a wide land I03 and a narrow land I04, with said wide landnormally sealing communication between the passage IM and the chamber I02 as indicated in Fig. 3. The brake valve I00 is also provided with a chamber I05 which is in communication with the passage IN by a. port I06. The chambers I02 and I05 might be used in the brake valve I00, for purposes of illustration the unit is shown as com- ,prising a cup-shaped member I01 (see Figs. 3

and 6) slidably mounted in the-chamber I with its open end adjacent to the port I00 and said cup-shaped member is pressed by a spring I00 toward the above mentioned internal flange. The closed end of the cup-shaped member is provided 1 H2 and passage II3 back to the reservoir or with a central port I09 and said member internally thereof carries a plurality of disks which function when pressure fluid is in the chamber I05 to cause said fluid to follow a tortuous path position therein bya screw I01a. The disks I01b of one type have their circumferences arcuately cut away to provide a land which fits the bore sump. whereupon the pressure in the brake cylinder 94 is reduced to a predetermined relative low pressure and the brake is held lightly applied as long as the control lever 14 is in the brake" position, thus permitting the spindle I1 to be turned by hand for loading purposes.

.It will be understood that by this means the brake is held applied with maximum pressure for a predetermined period due to the action of the time delay device in the brake valve I00 and then is held applied with a relative low predetermind pressure until the lever 14 is moved from brake position. Thus the spindle rotation is quickly stopped and the spindle is held in its stopped position, although it may be turned manually for loading or unloading purposes. The right hand end of the brake valve I00, as viewed in the drawing, is connected by a line I to a port I I5 located midway of the ends of the housing of a shuttle valve H6. The shuttle valve H6 is provided in its valve chamber with a slidable plunger II1 which when in its most right hand position, as viewed in Fig. 4, closes a port II! in the end of the shuttle valve and which port is connected with the line 02 that extends to the of the cup-shaped member and said cut-away portion with the interior of the cup-shaped memher and the adjacent disks provides an arcuate passage. The disks I01c of the other type interflt the interior of the cup-shaped member and are provided on their circumferences withslots forming connecting passageways between the arcuate passageways surrounding the disks I0'Ib. It will be observed that the slots in the circumferences of the disks I010 are alternately arranged on opposite sides of the lands of the disks III-1b. Consequently when the alternate disks I01b and I010 are assembled in the member I01, as shown in Fig. 6, a continuous tortuous passageway is provided through the member, it being noted that the slot in the disk I010 adjacent to the-opening or port I09 is provided with a groove I 01dextending from the circumferential slot to said opening. The time required for the pressure fluid to flow through the member I01 may be varied by increasing or decreasing the number of disks.

When the control lever 14- is moved into brake position as shown in Fig. 4 to cause pressure fluid at full line pressure to flow into the brake cylinder to apply the brake with maximum I pressure and into the chamber I05 of the brake valve, it will be seen that said pressure fluid after a suitable time delay will flow through the port I09 and act on the left hand side (as viewed in the drawing) of the valve plunger in the chamber I02 and move said plunger toward the right until the wide land I03of the plunger passes to the right of the exit of the passage IOI into the chamber I02. At this time the further right hand movement of the valve plunger is positively arrested and the pressure fluid in the passage IOI may now flow through the'chamber between the tion with the line I I4.

forward clutch 20. 'At this time the port H0 in the opposite end of the shuttle valve is open and said port is connected by a line I20 with the line 9| that extends to the reverse clutch 2I.

In Fig. 3 the position of the plunger 1 of the shuttle valve is at the opposite end of the valve housing from that shown in Fig. 4 and at such time the port I I9.is closed by the plunger and the port H8 is open and therefore is in communica- Hence it will be seen that after the brake has been applied and the plunger of the brake valve J00 moved to its most right hand position, as indicated in Fig. 4, it will be restored automatically to its original and left hand position as indicated in Fig. 3 as soon as the operator moves the control lever 14 to either the forward or the reverse position to cause pressure fluid to flow in the line 82 or SI to engage the forward clutch 20 or the reverse clutch 2i to effect forward or reverse drive of the spindle. Therefore the brake mechanism is reset drive is imparted to the spindle.

It will be understood that since the plunger of the brake valve I00 moves toward the left to be restored to its'original position if any pressure is built up between the left hand end of the plunger and the cup I01 sumcient to overcome the action the port I2I into the passage IOI. It will be noted also that any fluid which is at the right of the plunger as viewed in Fig. 3, can drain through the shuttle valve and through the selector valve to the sump when the plunger moves toward the right during the application of the brake.

The manual operation of the control lever for effecting the engagement and disengagement of the forward clutch 20 and the reverse clutch 2| to efiect forward or reverse rotation of the spindle and the application of the brake having been described the arrangement whereby said control lever 10 is utilized to initiate the automatic cycle of the speed changing operation will now be described.

Assuming that the machine is functioning in the first operative step of the work cycle whereautomatically for its operative cycle each time the brake has been applied as soon as a working in the work spindle I1 is rotating in the forward direction at a certainspeed and at this time the spools 63 and 54 are in their separated or indexing position as shown in Fig. 3, it will be noted that the spring pressedinterlock rod I22 is in' its spring retracted position as indicated in Fig. 3 and therefore is out-of engagement with any of therecesses or openings 53 in the interlock drum 51 fixed to the shaft 66. Consequently the operator can now index the spools 63 and 64 by rotating the hand wheel 56 to preselect the spindle speed desired for the next or second opera-. tive step of the cycle. Assuming that the spindle is to continue torotate in the forward direction in the next or second operative. step but .at a different speed than during the first step,

the operator as soon as the first operative step is completed moves the control lever 14 from "forward position to "neutral position and then rocks said lever inwardly toward the headstock as indicated in dot and dash lines-in Fig. 2. When the control lever I4 is in "neutral" position it overlies the outer end I23 of the shift lock rod I22 is pushed toward the interlock drum 51 by, the cam portion I24 on the plunger 68 until the outer end of the rod I22 engages in the opening 58 of the drum that is aligned with the rod to lock the drum and the shaft 55 against indexing rotation by the operator during the gear shifting operation. At this time the opposite end of the rod I22 is in the cam groove I25 on the plunger 68and the spring on said rod I22 is compressed. Therefore the rod I22 not only holds the interlock drum 51 against rotation but also at this time holds the plunger 68 against Y the reservoir through line Ila. After the plunger 68 has moved to the position shown in Fig. 4 the line 65 is in communication with the line I26, since the ports inthe shift valve housing to which the lines 65 and I26 are connected both now lie intermediate the lands 69 and 16 of the plunger 68. At this time the land I84 on the left hand end of the plunger 68 is engaging the left hand end of the housing of the shift valve 66 and is covering a port I21 in said end of the housing. Any pressure fluid to the left of the land I84 is free to return to the reservoir or sump through line I63, ports I66 and I65 of the spool shifting ,unit, later to be described, and line I86 which leads to the sump. Theline I26 extends to and is connected with a port I28 formed in the housing of an interrupter valve I29 which is now in the position shown in Fig. 3. The shifting of the plunger 68 into the position shown in Fig.

4 does not immediately cause the plunger I36 of l0 the interrupter valve I29 to move out or the position in which it is shown in Fig. 3 and consequently at this time the port I28 and. the line I26 are in communication with the port I3I of the interrupter valve and the line I32 connected to said port and leading to the reset valve later to be described, it being noted that the ports I28 and I3I are located intermediate the lands I38 and I34 of the plunger I36. Therefore pressure fluid now flows through the lines and I28, the

interrupter valve I29, the line I32 and into the end of the reset valve I 35 to move the plunger of said reset valve against the action of the valve spring from the position shown in Fig. 3 into the position shown in Fig. 4. At such latter time the line 64 from the relief valve 63 and connected to a port in the housing of the reset valve I36 is in communication with the line I36 also connected to a port in th housing of the reset valve I35 and leading to a crawl speed valve later to bedescribed, it being noted that said ports at this time lie intermediate the lands I31 and I38 of the valve plunger. Therefore pressure fluid from the line 64 flows through the reset valve I35 and through the line I36 to the crawl speed valve I 39.

The crawl speed valve I39 Is provided with two chambers separated by an internal flange I46. A time delay device, indicated generally at I and similar to the time delay device of the brake valve I66, is mounted in one of said chambers and said line I 36 communicates directly with this latter chamber. It will be noted that said latter chamber is also in communication with a passage I42 formed in the housing of the crawl speed valve I39 and communicating at one of its ends with the outer chamber of said valve and at its opposite end with line I43 leading to the cylinder 49 of the crawl speed clutch. Therefore since pressure fluid is in the line I36 it flows through the first mentioned chamber of the crawl speed valve I39 and into the passage I 42 and into the line I43 and causes the piston I44 of the crawl speed clutch and which issplined on the shaft 25 to shift'in' the clutch cylinder to bring the friction plate carried by the piston into engagement with a friction plate carried by the hub of the worm wheel I45 which meshes with the worm 48 previously referred to. Consequently the shaft 25 now will be driven from the shaft I9 through the shaft 41 at a slow non-workin or crawl speed to facilitate the shifting of the gearing.

The crawl speed valve I39 has slidably mounted in the otherof its chambers a plunger formed witha wide land I46 and a narrow land I41 and prior to pressure fluid entering the line I36 said wide land I46 closes the end of the passage I 42 opposite to the end to which the line I43 is connected (see Fig. 3). However, when pressure fluid enters the crawl speed valve I39 from the line I36 it will, after a predetermined delay, pass through the time delay device I 4i and into the chamber containing said plunger and will act to move said plunger from the position shown in Fig. 3 into the position shown in Fig. 4, it being understood that the crawl speed clutch 49 remains engaged during this time period. As soon as the plunger of the crawl speed valve I39 is in the position shown in Fig. 4 the passage I 42 in said valve is in communication between the lands I46 and I4! of the plunger with a passage I48, wherefore pressure fluid in addition to flowing from the line I36 through the valve I39 and into 76 the line I43 also now flows through the passages a 11 m and m and into line I49 which is connected to the end of the interrupter valve I29. The line The pressure fluid flowing from line I49 into the interrupter valve I29 must first pass through a time delay device I53 similar to the time delay devices I01 and Ill and is in the position shown in Fig. 3 for a purpose later to be explained. The pressure fluid in line I50 connected to the spool shifting unit and in the passage II acts on a large piston I54 and on a valve plunger I55 to shift said piston and plunger from the position shown in Fig. 3 into the full, line position of Fig. 4, assuming that the shifted gears properly intermesh.

The piston I54 is connected to a piston rod I55 that is slidable in suitable bearing openings formed in the housing of the spool shifter unit I52 (see Figs. 3 and 4). The piston rod I 55 has fixed thereto a yoke I51, the fork of which straddles and engages in an annular groove in the spool 53 (see Figs. 3 and 5). The rod I55 also has fixed to it a rack I58, and said rackmeshes with a pinion I59 which in turn meshes with a rack I50 carried by a rod I5I slidably mounted in the housing of the spool shifter unit to move parallel to the rod I55 but in the opposite direction. The rod I5I has fixed thereto a yoke I52, the fork of which straddles and engages in an annular groove formed in the spool 54. Consequently when the piston I54 is moved from the position shown in Fig. 3 into the full line position of Fig. 4 the spools 53 and 54 are moved from their separated indexing position toward each other with an equalized movement to cause the projections on the adjacent faces of the spools to act on the gear forks 50, 5| and 52 to move the same in a predetermined manner to shift the gear cones to obtain the spindle speed selected or preselected by the indexing of the spools previously referred to. In those instances whereinthe gears immediately intermesh properly and the piston I54 moves to its full right hand position on the flrst stroke, the interrupter valve I29 remains in the position shown in Fig. 3, since the time delay to the passage of pressure fluid through the device I53 is greater than the period -required for the full stroke of the piston I54.

Assuming that the gears which are to be intermeshed by the shifting have a relationship such that the gear teeth cannot mesh, then the movement of the piston I54 toward the right may be arrested before it reaches its full line position of Fig. 4 and in the intermediate position indicated by dotted lines therein. However, the valve plunger I55 in the spool shifting unit has moved completely to its full right hand position, as indicated in Fig. 4, and wherein the plunger land covers the port I 53 while the ports I54 and I55 are placed in communication with each other as are the ports I55 and I51. Any pressure fluid compressed in line I85 by the movement toward the right of the plunger of the crawl speed valve I39-returns now to the reservoir through ports I54 and I55 and line I85. I

The stopping of the movement of, the piston I54 before 'it reaches its full right hand position causes the pressure of the fluid in lines I50 and I49 to build up and to shift the time delay device I53 of the interrupter valve I29 against the action of its spring from the position shown in Fig. 3 into the position shown in Fig. 4. The buildup of pressure in line I49 as just referred to is in- 12 suillcient to overcome the spring which maintains the ball valve I58 seated-in the housing of the crawl speed valve I39. As soon as the time delay device I53 has been shifted into the position shown in Fig. 4 the pressure fluid in line I49 is free to by-pass the time delay device and flow through passage I59 in the housing of the interrupter valve I29 and into the valve chamber to act immediately on the land I10 of the plunger I30 to shift said plunger from the position shown in Fig. 3 into the position shown in Fig. 4. At this time the pressure fluid flowing from the shift valve and line I25 through port I28 into the interrupter valve is trapped between the lands I33 and I34. Also at this time the pressure fluid in line I32 which connects the port I3I with the upper end of the reset valve I35 is free to return to the sump through port I13 and line I14 and therefore pressure against the end of the reset valve plunger is relieved and said valve plunger is moved by its spring from the position shown in Fig. 4 back to the position shown in Fig. 3. At this time the pressure'fluid in line I35 from the reset valve and in the crawl speed valve I39 returns from said line to the reservoir through the port I15 and line I15 and thus the crawl speed clutch is disengaged and the pressure against piston I 54 is relieved. Also at this time the pressure fluid in line 54 from the relief valve can flow through the reset valve I35 (now in the position of Fig. 3) through ports I11 and I18 now located between the lands I 31 and I33 of the reset municates with the right hand ends of the chambers in which the piston I54 and valve plunger I55 are located. Consequently pressure fluid now acts on said piston and plunger to move the same toward the left into the position of Fig. 3, thus separating the spools 53 and 54 and relieving the force tending to shift the gears that do not intermesh.

The movement of the piston I54 and the plunger I55 into the position of Fig. 3 causes the pressure fluid from line I19 to flow through ports I53 and I54 of the gear shifting unit into line I85 leading to the right hand end of the crawl speed valve I39, with the result that the plunger of said crawl speed valve is shifted from the position shown in Fig. 4 into the position shown in Fig. 3

with the wide land I45 interrupting communication between the passages I48 and I42, of said crawl speed valve and thus relieving pressure in line I49 leading to the lower end of the interrupter valve which is still in the position shown in Fig. 4. As soon as this occurs the spring of the time delay device I53 moves the cup-shaped member of said device into. the position of Fig. 3, thus closing communication between the line I49 and the by-pass passage I59 Of the interrupter valve. The spring of the interrupter valve acts on the plunger I30 to move the same from the position shown in Fig. 4 into the position shown in Fig. 3, it being noted that any fluid trapped between the land I10 of said plunger and the time delay device I53 can escape through said device through line I49, passage I48 Of the crawl speed valve, the ball valve I58 and into passage I35 and back to the sump through the reset valve and passage I15, it being understood that the strength of the spring in the interrupter valve is suflicient to overcome the spring acting on the ball valve I55. At this time pressure fluid imme- I 28, ports I20 and ill of interrupter valve I23 into line I32, whereupon the plunger of the reset valve I35 is moved from the position shown in Fig. 3 against its spring into the position shown in Fig. 4, and line 04. from the relief valve is again connected through'the reset valve with line I36 and pressure fluid is flowing through the crawl speed valve I38 to the crawl speed clutch 48 to engage said clutch and cause a slow non-working rotation to be imparted again to the gearing. Also at this time line I18 from the spool shifting unit I is connected to the reservoir through the reset valve I35, port I8I and line I82 so that now there is no pressure fluid acting on the piston"! to move the same toward the left. The instant that the pressure fluid again flows through crawl speed valve I38 pressure fluid also again flows into the passage II to act on the piston I53 and plunger I55 to move the same toward the right and to cause the spools to move toward each other and complete the shifting of the gears. v

From the foregoing it will be seen that in the operation of the automatic gear shifting cycle if the gears do not intermesh the pressure builds up to cause the shifting movement thereof to cease; the gears are given a further slow rotation, and then the shifting movement is repeated to bring the gears into full intermesh relationship. The

operation whereby the shifting of the gears is momentarily stopped and then resumed to prevent gear clashing or injury will be repeated automatically if necessary until the gears can be intermeshed quietly and easily.

Assuming that the gear shift has been completed and the gears intermeshed, the piston I54 will hav completed its stroke toward the right to the full line position of Fig. 4, it being recalled that plunger I55 is also in its most right hand position as indicated in Fig. 4. As soon as the piston I54 has reached its most right hand position pressure fluid flows from the cylinder in which the piston operates, through the port I61, through the cylinder in which the plunger I55 operates, through port I66 and into line I83 and acts on piston head I84 on the left hand end of the plunger 68 of shift valve 66 to move said plunger from the position shown in Fig. 4 into the position shown in Fig. 3. Therefore the shift valve 66 is restored to its initial position and the.

- operation.

As soon as the shifter valve is restored to its original position of Fig. 3 communication between line 65 from the relief valve and line I26 to the interrupter valve is interrupted, but line 65 is placed in communication with line H leading to the'selector valve 12 and since the control lever A 14 has already been moved to the forward position, pressure fluid flows from line 1 I through passages 15 and 16 of the valve plug 13 and into lines 18, 80 and 82 to the forward clutch 20 to engage said clutch and drive the transmission at the newly attained speed.

Inasmuch as line I26 from the shift valve to the interrupter valve is now disconnected from line 65 and is connected by line I81 to the sump,

pressure ,ln said line I26 and in line I32 leading to the reset valve immediately falls and the plunger oi reset valve I35 returns under the action of its spring from the position of Fig. 4 into the position of Fig. 3. The instant that the plunger of reset valve I35 returns to the position shown in Fig. 3, line I36 leading from the reset valve to the crawl speed valve is connected to the reservoir through line I16 and hence pressure fluid is not flowing through the crawl speed valve I38 into line I33 and the crawl speed clutch l8 is immediately disengaged. This return movel0 ment of the plunger of reset valve I35 occurs immediately upon the plunger 68 of the shift valve 66 being moved to its initial position and prior to the engagement of the forward clutch 20 and results in the crawl speed clutch 48 being disengaged before the engagement of the forward clutch. Since pressure fluid can flow from line 64 from the relief valve through ports I11 and I18 of the reset valve I35 into line I19 leading to the spool shifting unit and through passage I80 to move piston I54 and plunger I55 from their most right hand positions as shown in Fig. 4 to their most left hand positions as shown in Fig. 3, the'pressure fluid from passage I80 can now flow through port I63, port I64 and line I85 into the crawl speed valve I33 to move the valve plunger from the position shown in Fig. 4 to reset the same in the position shown in Fig. 3, at which time the wide land I36 interrupts the communi cation between passages I42 and I48 of the crawl speed valve.

The movement of the piston I54 from the position of Fig. 4 to the position of Fig. 3 effects equalized separating movement of the spools 53 v and 53 to move the same to indexing position, it being recalled that said spools can now be indexed since the rod I22 is not holding. the interlock drum 51 against rotative movement. Aslong as the shift valve plunger and the reset valve are in the position of Fig. 3, the piston I53 and plunger I55 are-held in their left hand position and the spools are maintained in separated indexing position. Any pressure generated in the passage I5I by the leftward movements of the piston I53 and plunger I55 is transmitted by line I50, line 3 to-passage I48 of the crawl speed valve 439 and such pressure may act to unseat the ball valve I68 and the pressure fluid can return by pray of the line I36 through the reset valve and line I16 to the reservoir.

that the cycle of the gear shifting operation is carried out automatically and is initiated manually by the momentary inward movement of the control lever when in neutral position to move 35 the plunger 68 of the shift valve 66 from the position of Fig. 3 to the position of Fig. 4. It will have been noted that said plunger 68 upon the completion of the gear shifting operation is restored automatically to its original position of 00 Fig. 3. It will also have been observed that the inward movement of the plunger 68 to initiate the gear shifting operation acts to position the interlock rod I22 to prevent turning of the interlock drum 51 and the shaft 55 during the gear shift- 05 ing operation and hence the operator cannot inadvertently index the spools 53 and '54 when the gears are being shifted.

It will also be noted that the restoration of the plunger 68 of the shift valve 66 to its initial 70 position automatically acts to effect the disengagement of the interlock rod I22 from the openings in the interlock drum and thus as soon as the shift valve plunger 68 is in its initial position the spools 53 and 54 which have been sepa- 73 rated automatically at the conclusion of the gear From the foregoing description it will be seen different spindle speed.

Assuming that the third operative step of the work cycle calls for a different speed of the spindle than the second step and that the spindle is to rotate in the reverse direction during the third step the following occurs: During the secondoperative step of the cycle the operator turns the hand wheel 56 to the desired position to index the spools 53 and 54 to preselect the spindle speed for the third operative step. Upon the completion of the second operative step the operator moves the control lever 14 from forward position into neutral position to disengage the forward clutch 20 and he momentarily pushes said control lever while in the neutral position inwardly to move the shift valve plunger 68 from the position shown in Fig. 3 to the position shown in Fig. 4 and initiate the automatic gear shifting cycle and then he swings the control lever 14 from neutral position into reverse position. The gear shifting operation is effected automatically in the manner previously described and as soon as the shift valve plunger 68 has been returned from the position of Fig. 4 into the position of Fig. 3 at the conclusion of the gear shifting operation the pressure fluid from line H from the shift valve flows through passages 15 and l6 in the selector valve plug 13 and into port 90 of the selector valve and through line 9| to the reverse clutch 2| and causes the engagement of said clutch, whereupon the spindle will be rotating at thepreselected speed'for the third operative step and in the reverse direction. In this way the spindle speeds and direction of rotation can be obtained for each operative step of the work cycle and at the end of the last operative step the operator can move the control lever 14 into neutral position to disengage both the forward and reverse clutches and if desired he can move said control lever into brake position to apply the brake in the manner previously described. The detailed description herein set forth clearly points out that the construction embodying the present invention accomplishes the objects enumerated at the start of this specification and reference to said objects is in order;

Although a preferred embodiment of the invention has been illustrated and described herein it will be understood that the invention is susceptible of various modifications and adaptations within the scope of the appended claims.

Having thus described my invention, I claim: 1. In a machine tool having a movable part, a transmission for imparting working speeds to said part and including shiftable gears, shifting means connected with said gears and movable from a speed selecting indexing position to a gear shifting position, mechanism for moving said shifting means to and from said positions and including a pressure fluid motor, means for imparting a crawl speed to said transmission to facilitate the shifting of said gears and including a clutch and a pressure fluid motor for engaging a said clutch, a pressure fluid supply source, control means for causing sequential operation of said motors and including pressure fluid lines interconnecting said motors and said source, a reset valve in said lines and normally causing said first motor to move said shifting means to indexing position and normally interrupting communication between said second motor and said source to maintain said clutch disengaged, a shift valve in said lines and manually movable from a normal position to an active position to initiate a complete automatic gear shifting cycle and to cause movement of said reset valve from its normal position to a position wherein said second motor is placed in communication with said source to effeet engagement of said crawl speed clutch while said first motor is momentarily disconnected from said source, a time delay device interposed in the line between said second motor and said reset valve and connected to said first motor and including a control valve movable automatically from a normal position after a predetermined time delay to a position to connect said first motor through said device with said source, to cause gear shifting operation thereof, and a valve 5 operatively associated with said first motor and automatically movable from a normal position when said motor is thus operated to cause automatic restoration of said shift valve, said reset valve and said control valve to their normal po- 20 sitions with a consequent operation of said first motor to restore said gear shifting means to indexing position and said last valve to its normal position and to cause interruption of the communication between said second motor and said /source to disengage said clutch.

2. In a machine tool having a movable part, a transmission for imparting working speeds to said part and including shiftable gears, shifting means connected with said gears and movable from a speed selecting indexing position to a gear shifting position, an indexible member operatively associated with said shifting means for indexing the latter, mechanism for moving said shifting means to and from said positions and including a pressure fluid motor, means for imparting a crawl speed to said transmission to facilitate the shifting of said gears and including a clutch and a pressure fi uid motor for engaging said clutch, a pressure fluid supply source, 40 control means for causing sequential operation of said motors and including pressure fluid lines interconnecting said motors and said source, a

. reset valve in said lines and normally causing said first motor to move said shifting means to 5 indexing position and normally interrupting communication between said second motor and said source to maintain said clutch disengaged, a shift valve in said lines and manually movable from a normal position to an active position to initiate a complete automatic gear shifting cycle and to cause movement of said reset valve from its normal position-to a position wherein said second motor is placed in communication with said source to effect engagement of said crawl 5 speed clutch while said first motor is momentarily disconnected from said source, an interlock element actuated by said shift valve during its said manual movement to lock said indexible member against indexing movement, a 00 time delay device interposed in the line between said second motor and said reset valve and connected to said first motor. and including a control valve movable automatically from a normal position after a predetermined time delay to a position to connect said first motor through said device with said source to cause gear shifting operation thereof, and a valve operatively associated with said first motor and automatically movable from a normal position when said motor is thus operated to cause automatic restoration of said shift valve, said reset valve, said control valve and said interlocking element to their normal positions with a consequent operation of said first motor to restore said gear shifting means to indexing position and said last named valve to its normal position and to cause interruption of the communication between said second motor under the built-up pressure in the line between said interrupter valve and said first motor when said first motor is unable to complete the shifting of the gears to cause a restoration of the reset valve to normal position to effect reverse operae tlon of said first motor and a disengagement oi the crawl speed clutch and then said plunger is automatically movable back to normal position upon the diminution of the built-up pressure to cause movement of said reset valve from normal position to a position wherein said second motor is actuated to engage said crawl speed clutch and said first motor is actuated in a gear shifting direction.

4. In a machine tool as defined in claim 1, a power source, a second clutch for connecting the transmissionto said power source for operation at different working speeds, pressure fluid perated means for actuating said second clutch, a selector valve connected to said pressure fluid operated means and to said source of pressure fluid supply through said shift valve when the latter is in normal position, said selector valve being movabie to selectively cause engagement or disengagement of said second clutch, said selector valve being disconnected from said source of pressure fluid supply when said shift valve is manually moved from said normal position to said active position to initiate the automatic gear shifting cycle.

5. In a machine tool as defined in claim 1, a power source, a second clutch for connecting said power source with said transmission for imparting working speeds to, said part, pressure fluid operated means for actuating said second clutch, a selector valve for controlling said pressure fluid operated means and connected thereto and to said pressure fluid supply source through said shift valve when the latter is in its said normal position, and a manually operated control member operatively connected with said selector valve 'to effect engagement or disengagement of said second clutch and operatively associated with said shift valve to effect the movement thereof from its said normal position to its said active position to initiate the automatic gear shifting cycle.

6; In a machine tool as defined in claim 1, a power source, a second clutch for connecting said transmission to said power source for operation at working speeds, pressure fluid operated means able in another plane to effect shifting of said shift valve from its said normal position to its said active position to initiate the automatic gear shifting cycle.

7. In a machine tool having a movable part, a brake mechanism operatively associated with ,18 said part for, braking the movement thereof, pressurefluid operated means for actuating said brake mechanism, a, pressure fluid supply source. means interconnecting said pressure fluid operated means with said source, a selector valve movable from a position wherein said interconnecting means is interrupted to a position wherein said pressure fluid operated means is subjected to full line pressure, a brake valve connected to said interconnecting means intermediate said pressure fluid operated means and said selector valve and including a time delay device, a valve plunger "moved by the pressure fluid passing through said time delay device to cause the pressure fluid to partially by-pass said device and act on a spring controlled valve element to move the latter under predetermined pressure to reduce the pressure of the pressure fluid flowing to said pressure fluid operated means whereby said brake mechanism is first applied with full force and then after a predetermined time delay automatically is maintained applied with a predetermined reduced force.

8. In amachine tool as defined in claim I, a

' power source, clutches for connecting saidpower and functioning when either of said clutches is engaged to automatically restore the plunger of said brake valve to normal position.

9. A time delay device adapted to be used in a pressure fluid circuit and comprising a housing member having a longitudinally extending opening therein, means located in said housing and filling said opening, said means being provided with longitudinally spaced peripheral cutouts forming narrow land portions and with said housing peripheral passages embracing said means and extending from one side of said lands to the other side thereof, said means being provided intermediate said peripheral passages with slots interconnecting said peripheral passages, said slots being located alternately on opposite sides of said land portions, said peripheral passages and said slots together forming a tormous passageway through said device.

10. A time delay device adapted to he used in a pressure fluid circuit and comprising a housing having a longitudinally extending opening therein, a plurality of disks located within said opening and of a size to interfit the same, said disks being arranged in two serie with the disks of one series alternating with the disks of the other series, the disks of one series each being cut away on its periphery to provide a relatively narrow land portion and a peripherally extending cutout forming with said housing and the adjacent disks an extended passageway from one side of said land portion to the other side thereof, the disks of the other series eachbeing provided with a slot interconnecting the adjacent peripheral passageways, the disks of said other series being so located with respect to the disks of said one series that said slots alternately are onopposite sides of the land portions of the of said one series whereby a tortuous passageway is formed through the device which extends 19 around the disks oi the one series and thro gh the slots of the disks *of the other series.

- 11. In combination, a cylinder, 2 plunger movable therein, a pressure fluid supply source, means for connecting said cylinder and said source, and a time delay device interposed between said plunger and said source and including a housing member having a longitudinally peripheral passageways from one side of said land portions to the other side thereof, said means also being provided intermediate said cutouts with slots interconnecting said peripheral passageways and located alternately on opposite sides of and close to said land portions to form a tortuouspassageway through said member whereby a predetermined time delay occurs in building up pressure in said cylinder to move said plunger.

12. In a hydraulic control for a machine tool having a movable part as defined in claim 1 and wherein there is a power source for actuating said transmission, a brake mechanism operatively associated with said movable part for braking the movement thereof, "pressure fluid operated means for actuating said brake and mechanism, means interconnecting said pressure fluid operated means with said pressure fluid supply source, a selector valve movable from a position wherein said interconnecting means is interrupted to a position wherein said pressure fluid operated means is subjected to full line pressure, a brake valve connected to said interconnecting means intermediate said pressure fluid operated means cause the pressure fluid to partially by-pass said device and act on a spring controlled valve element to move the latter under predetermined pressure to reduce the pressure of the pressure fluid flowing to said pressure fluid operated means whereby said brake mechanism is flrst applied with full force and then after a predetermined time delay automatically is maintained applied with a predetermined force, clutches for connecting said power source with said transmission to drive the latter in opposite directions, a second pressure fluid operated means for actuating said clutches, said selector valve being connected with said second pressure fluid operated means and movable to a position to control engagement and disengagement of said clutches, and a shuttle valve connected with said selector valve, said brake valve and said second pressure fluid operated means and functioning when either of said clutches is engaged to automatically restore the plunger 01' said brake valve to normal position.

. FAY M. TOMLINSON.

imFEREucEs CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

